1. Field of the Invention
The present invention generally relates to the management of database generated events, and more specifically to a database event detection and notification system using a Type Abstraction Hierarchy (TAH).
2. Description of the Related Art
The retrieval and display of critical and timely data is essential in modern information systems. Database triggering is one approach to achieve this goal. It is applicable to complex, dynamic databases that require advanced information management capabilities to identify and act on changes in critical data. Such systems have a wide range of usage in both military (e.g. logistic planning, crisis management, etc.) and commercial users (e.g., fraud detection, inventory control, logistics planning, risk management, health care information system, etc.).
The trigger mechanisms in commercial relational database systems (RDBMS) such as Oracle, Sybase, etc. process active Event-Condition-Action (ECA) rules on low-level events, such as insert, update, delete, etc. Further, these mechanisms are based on exact trigger conditions and actions.
However, real world trigger conditions and actions are often inexact, uncertain, user and context sensitive, and are represented by concepts. For this reason, database triggering has been limited to simple applications in which the triggering rules can be entered exactly. A system for specifying conceptual event triggering and notification rules to a database system has not heretofore been proposed.
To handle inexact and uncertain conditions, the present invention provides a new active database technology that the inventor has named the xe2x80x9cCooperative Sentinel (CoSent) Systemxe2x80x9d, which supports active rules with conceptual terms (e.g. heavy, large) and approximate operators (e.g. similar-to, near-by). As a result, it is much easier for rule specification and maintenance. Further, CoSent also supports distributed composite events.
More specifically, the CoSent system is a database event detection and notification system which includes a rule definer for defining a high level rule which can include a conceptual term such as a cooperative operator (e.g. approximate, similar-to, near-to). A rule converter converts the high level rule into a low level rule in which the conceptual term is quantified.
An event manager detects and evaluates an event generated by the database or a Local Event Detector (LED). A rule manager applies the low level rule to the event detected by the event manager, and an action manager performs an action in accordance with the application of the rule by the rule manager. The action can include notifying a specified person or program that the event has occurred.
The rule converter and the action manager utilize a Type Abstraction Hierarchy (TAH) for converting the high level rule into the low level rule and performing the action respectively. The rule comprises events, conditions and actions which can be described by the attributes. The TAH comprises leaves corresponding to instances of the attribute, and a hierarchical arrangement of nodes which specify ranges that include at least one of the instances respectively.
As shown in FIG. 9, the rule converter consists of a rule decomposer 90, rule definition macro 88, and a rule translator 92. The rule decomposer 90 based on the user type, context and rule definition converts the high level (English-like) rule into a set of specific low level rule(s). The rule translator 92 based on the specific TAHs translates the conceptual terms and approximate terms in the rule into value ranges.
These and other features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings, in which like reference numerals refer to like parts.